Bug: Randart with a cooldown-less activation

[ThatGitMITZE]

Got a nice pair of randart sandals from Gothmog...

the Pair of Leather Sandals Enyath [1,+14] <+5, +2, +1> {@w4@A4} Dropped by Gothmog, the High Captain of Balrogs, in Angband 96

 +5 strength.
 +2 dexterity.
 +1 light.
 Provides resistance to acid (35%), fire (64%), cold (50%), poison
 (40%), light (50%), dark (45%), sound (50%), shards (35%), nexus
 (50%), disenchantment (45%).
 Provides protection from fear, blindness.
 Cannot be harmed by acid, fire.
 Slows your metabolism.  Feather Falling.  

 When activated, it hastes you for 20+d20 turns.
 Your chance of success is 97.4%

As you can see, there's no cooldown on the activation—and that isn't a display error. I've taken to equipping it and then activating it a bazillion times in a row while waiting on recall and such, the speed just never wears off as long as I'm being proactive...

EDIT: Webserver nightly

[ThatGitMITZE]

Not fixed, sasquatch found another one on webserver nightly, activates for heal 5d20.

[NickMcConnell]

Also Nimphelos, so not just randarts

[backwardsEric]

Is it known if sasquatch's artifact with a broken timeout was a light? If it was, then #404 should fix future occurrences of similar artifacts as well as fixing the timeouts for standard artifact lights.

[ThatGitMITZE]

I believe sasquatch's randart was footwear.